Damper

Abstract

The present invention includes a damper assembly, method and kit to provide dampening to an airframe comprising: a mass to dampen the vibration of the airframe; one or more wire rope isolators having a first and a second portion, wherein the mass is attached to the one or more wire rope isolators and the mass is isolated from the airframe by the one or more wire rope isolators; and a first fastener and a second fastener, wherein the first fasteners attaches to the first portion of the wire rope isolator to the mass, and the second fastener attaches the second portion of the wire rope isolator to the airframe to dampen vibration of the airframe.

What is claimed is: 
     
       1. A passive damper assembly for an airframe comprising:
 a mass to damp a vibration of the airframe; 
 one or more wire rope isolators having a first and a second portion, wherein the mass is attached to the one or more wire rope isolators and the mass is isolated from the airframe by the one or more wire rope isolators, wherein a shear stiffness and a cross-sectional geometrical shape of each of the one or more wire rope isolators are selected to provide frequency isolation of the mass in two or more known excitation frequencies; and 
 a first fastener and a second fastener, wherein the first fastener attaches to the first portion of the wire rope isolator to the mass, and the second fastener attaches the second portion of the wire rope isolator to the airframe; 
 wherein the damper assembly is connectable to the airframe such that it is configured to provide isolation based on shear only or based on compression only. 
 
     
     
       2. The damper assembly of  claim 1 , wherein a stiffness, a compression/shear, a compression/roll, and the cross-sectional geometrical shape of each of the one or more wire rope isolators are selected to provide frequency isolation of the mass in the two or more known excitation frequencies. 
     
     
       3. The damper assembly of  claim 1 , wherein the first fastener or the second fastener is selected to attach the damper assembly to a rotorcraft or vertical take-off and landing craft. 
     
     
       4. The damper assembly of  claim 1 , wherein the first and second portions of the one or more wire rope isolators are along a side of the one or more wire rope isolators. 
     
     
       5. The damper assembly of  claim 1 , wherein the mass is connected by 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more wire rope isolators that are positioned on one or more sides of the mass. 
     
     
       6. The damper assembly of  claim 1 , wherein the mass is positioned within an airframe, at an end of the airframe, at an end of a tail of the airframe, along a length of the tail boom, or a combination thereof. 
     
     
       7. The damper assembly of  claim 1 , wherein the one or more rope isolators comprise a ceramic. 
     
     
       8. The damper assembly of  claim 1 , further comprising a coating on the mass. 
     
     
       9. The damper assembly of  claim 1 , wherein the mass or the first or second fasteners are a metal, a composite, a polymer, a ceramic, an alloy, or a combination thereof. 
     
     
       10. The damper assembly of  claim 1 , wherein the one or more wire rope isolators comprise fiber strands, fiber wires, polymer strands, polymer wires, lubricating oil, a polymer, an adhesive, a filler, a coating, a composite, or a combination thereof. 
     
     
       11. The damper assembly of  claim 1 , wherein a wire rope of the one or more wire rope isolators is selected from a size, a cross-sectional geometrical shape, and a strength of the wire rope in one or more dimensions based on at least one of: (1) a rope bending length  1 ; (2) a diameter D of sheave or drum; (3) one or more simple bendings per working cycle w-sim; (4) one or more reverse bendings per working cycle w-rev; (5) a combined fluctuating tension and bending per working cycle w-com; (6) a relative fluctuating tensile force deltaS/S; or (7) a rope tensile force S. 
     
     
       12. The damper assembly of  claim 1 , wherein the vibration is adjusted in two or more frequencies based on the shape, a size, a compressive strength, a rotational strength, or a pull strength of the one or more wire rope isolators. 
     
     
       13. The damper assembly of  claim 1 , further comprising one or more tuning weights attached to the mass, the one or more wire rope isolators, or both. 
     
     
       14. A method for passively damping vibration of an airframe comprising:
 providing a mass to dampen the vibration of the airframe; 
 selecting one or more wire rope isolators having a first and a second portion, wherein the mass is isolated from the airframe by the one or more wire rope isolators, and wherein a shear stiffness and a cross-sectional geometrical shape of each of the one or more wire rope isolators are selected to provide frequency isolation of the mass in two or more known excitation frequencies; and 
 attaching the mass to the one or more wire rope isolators and the one or more wire rope isolators to the airframe, wherein one or more first fasteners attach the first portion of the one or more wire rope isolators to the mass, and one or more second fasteners attach the second portion of the one or more wire rope isolators to the airframe, such that the mass and the one or more wire rope isolators are configured to dampen vibration based on shear only or based on compression only. 
 
     
     
       15. The method of  claim 14 , wherein a stiffness, a compression/shear, a compression/roll, and the cross-sectional geometrical shape of each of the one or more wire rope isolators are selected to provide frequency isolation of the mass in the two or more known excitation frequencies. 
     
     
       16. The method of  claim 14 , wherein the first fastener or the second fastener is selected to attach the damper assembly to a rotorcraft or vertical take-off and landing craft. 
     
     
       17. The method of  claim 14 , wherein the first and second portions of the one or more wire rope isolators are at an end of the one or more wire rope isolators. 
     
     
       18. The method of  claim 14 , wherein the mass is connected by 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more wire rope isolators that are positioned on one or more sides of the mass. 
     
     
       19. The method of  claim 14 , wherein the mass is positioned within an airframe, at an end of the airframe, at an end of a tail boom of the airframe, along a length of the tail boom, or a combination thereof. 
     
     
       20. The method of  claim 14 , further comprising attaching one or more tuning weights to the mass, the one or more wire rope isolators, or both. 
     
     
       21. The method of  claim 14 , further comprising a coating on the one or more wire rope isolators. 
     
     
       22. The method of  claim 14 , wherein the mass or the first or second fasteners are a metal, a composite, a polymer, a ceramic, an alloy, or a combination thereof. 
     
     
       23. The method of  claim 14 , wherein the one or more wire rope isolators comprise fiber strands, fiber wires, polymer strands, polymer wires, lubricating oil, a polymer, an adhesive, a filler, a coating, a composite, or a combination thereof. 
     
     
       24. The method of  claim 14 , wherein a wire rope of the wire rope isolators is selected from a size, a cross-sectional geometrical shape, and a strength of the wire rope in one or more dimensions based on at least one of: (1) a rope bending length  1 ; (2) a diameter D of sheave or drum; (3) one or more simple bendings per working cycle w-sim; (4) one or more reverse bendings per working cycle w-rev; (5) a combined fluctuating tension and bending per working cycle w-com; (6) a relative fluctuating tensile force deltaS/S; or (7) a rope tensile force S. 
     
     
       25. The method of  claim 14 , wherein the vibration is adjusted in two or more frequencies based on the cross-sectional geometrical shape, a size, a compressive strength, a rotational strength, or a pull strength of the one or more wire rope isolators. 
     
     
       26. A passive mass damper kit for an airframe comprising:
 a mass selected to dampen a vibration of the airframe; 
 one or more wire rope isolators, each having a first and a second portion, wherein a shear stiffness and a cross-sectional geometrical shape of each of the one or more wire rope isolators are selected to provide frequency isolation of the mass in two or more known excitation frequencies, wherein the one or more wire rope isolators are selected to dampen airframe vibration; and 
 one or more first fasteners and one or more second fasteners, wherein the one or more first fasteners are adapted to attach the first portion of the wire rope isolator to the mass, and the one or more second fasteners are adapted to attach the second portion of the wire rope isolator to the airframe to dampen vibration of the airframe; 
 wherein the mass and the one or more wire rope isolators are connectable to the airframe such that it is configured to provide isolation based on shear only or based on compression only; and 
 instructions to attach the mass to the one or more wire rope isolators via the one or more first fasteners and to attach the one or more wire rope isolators to the airframe via the one or more second fasteners. 
 
     
     
       27. The passive mass damper kit of  claim 26 , wherein a stiffness, a compression/shear, a compression/roll, and the cross-sectional geometrical shape of each of the one or more wire rope isolators are selected to provide frequency isolation of the mass in the two or more known excitation frequencies. 
     
     
       28. The passive mass damper kit of  claim 26 , wherein a wire rope of the one or more wire rope isolators is selected from a size, a cross-sectional geometrical shape, and a strength of the wire rope in one or more dimensions based on at least one of: (1) a rope bending length  1 ; (2) a diameter D of sheave or drum; (3) one or more simple bendings per working cycle w-sim; (4) one or more reverse bendings per working cycle w-rev, (5) a combined fluctuating tension and bending per working cycle w-com, (6) a relative fluctuating tensile force deltaS/S, or (7) a rope tensile force S. 
     
     
       29. The passive mass damper kit of  claim 26 , wherein the vibration is adjusted in two or more frequencies based on the shape, a size, a compressive strength, a rotational strength, or a pull strength of the one or more wire rope isolators.